[coreboot-gerrit] Change in coreboot[master]: {mb, soc}: Change `memcfg_init()` and `variant_memory_init()` prototype

[Eric Lai (Code Review)]

Attention is currently required from: Tim Crawford, Sean Rhodes, Subrata Banik, Jeremy Soller, Tim Wawrzynczak, Nick Vaccaro, Patrick Rudolph, Zhuohao Lee.
Eric Lai has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/62736 )

Change subject: {mb, soc}: Change `memcfg_init()` and `variant_memory_init()` prototype
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Patch Set 1: Code-Review+1